In the Boston area, the bus drivers seem particularly likely to react to this by the second bus passing the first (even by crossing a double yellow: traffic laws are generally optional here).
In the article this is presented as a symptom of how bad the bunching is, but as a rider it feels like this helps the problem: new riders are now getting on the bus that's less full.
Passing would only be a temporary solution since the new front bus will now have the delayed position, and the more crowded bus that was passed will have the expedited position and will shortly overtake the front one. They will essentially travel at the same rate and stay bunched in this scenario.
It might make more sense, when the delay to the front bus gets to within a given time of the rear bus' expected arrival time (maybe 1 minute, maybe more, maybe less), the lead bus simply switches to a state where it only picks up when a stop is requested by a passenger until it gets to within some time differential from its scheduled arrival time.
That would suck for some people to watch it pass but realistically, if it wasn't skipping stops, the wait for leap-frogging platoon would be closer to that off the rear bus anyway.
In the article this is presented as a symptom of how bad the bunching is, but as a rider it feels like this helps the problem: new riders are now getting on the bus that's less full.